This invention relates generally to electrical connectors and, more particularly, to connectors for electrically connecting a flat multiconductor flexible cable to a printed circuit board.
The current and expanding use of solid state controls in numerous commercial and industrial applications has placed a great demand on interconnection systems particularly using flexible circuitry and flat multi-conductor cables to carry electrical signals to and from electrical components such as printed circuit boards. A variety of connectors for accommodating flexible circuitry and flat conductor cables is available, the connector construction being often determined by space requirements and size of the components to be inter-connected.
In an effort to provide a miniaturized, inexpensive connector, relatively large insulative housings including contact terminals with plug-and-socket fittings or soldered connections have been replaced with one-piece, formed connectors. Such connectors are shown and described, for example, in U.S. Pat. No. 4,111,510 to Zurcher and U.S. Pat. No. 4,060,889 to Zielinski. These connectors are limited, however, to making an interconnection at the edge of the printed circuit board.
Another known connector is disclosed in U.S. Pat. No. 4,169,641 to Olsson in which a one piece stamped and formed connector accommodates a flat multiconductor cable having one side of the conductors exposed for engagement with electrical conductors on a circuit board. A plurality of cantilever springs extending obliquely from a clip bar individually urge the cable conductors against the circuit board conductors when the clip bar is mounted to the board. The connector is attached to the board by mechanical fastening means such as bendable locking tabs at the ends of the connector that are bent against the underside of the board to rigidly and permanently hold the connector thereon. A similarly mounted connector is shown by Olsson in U.S. Pat. No. 4,181,386 in which a plurality of spring contacts are reversely bent at one edge, each contact having a spring arm portion that extends obliquely underneath the clip bar.
Such connectors, initially mounted rigidly have a tendency due to environmental conditions, such as vibration and temperature changes, to become loose since the fastening means lacks the flexibility to provide compensation for these variations. A loosened clip bar could cause a higher probability of the loss of inter-connection between conductors as there would be a decrease in the contact pressure provided by the spring members. Strain relief capability of a loosened connector, wherein such strain relief is provided by an integral portion of the connector, is also jeopardized.
In addition, removal of the connector to either replace or repair the cable or electrical components necessitates the operational steps of straightening the tabs as well as having access to the undersurface of the printed circuit board. Such bending and straightening of the tabs further weakens the structural integrity of the tabs particularly at the bending portion, resulting in less rigidity in the mounting and a reduction in the useful life of the connector.